Foot ulceration is a diabetic complication estimated to result in over $1 billion worth of medical expenses per year in the United States alone. Increasing evidence indicates that a combination of elevated external forces (pressure and shear) and altered tissue properties is of prime importance in the etiology of foot ulcers. Although commercial platform and in-shoe systems to measure plantar pressure are in clinical use, a system that can measure both horizontal shear and vertical pressure remains to be developed and commercialized. The overall goal of the proposed research is to develop a multipoint, insole system that can accurately characterize both pressure and shear across the plantar surface, is thin and flexible enough to provide minimal interference with normal foot-shoe interaction, can be easily manufactured, and holds calibration sufficient for research and clinical use. In our Phase I program we will develop an array of 9 sensors with the accompanying electronics that can accurately measure applied normal pressure as high as 700 kPa and shear as high as 200 kPa. We will integrate this array into a single thin, flexible, compliant structure that will form the basis for a Phase II insole system and we will perform laboratory testing using two specially developed test fixtures to demonstrate sensor array performance against our success criteria for size, accuracy and stability of calibration. Success in Phase I will lead to full-scale implementation of an insole system with over 100 sensors in Phase II. We also plan in Phase II to integrate the system with software in development for visualization of foot pressure and shear data (1 R43 DK61164-01A1, Phase II award pending). The combined insole sensor and visualization software system would then be evaluated with data collected from both diabetic and normal patients. Commercial availability of a complete hardware and software analysis system to measure pressure and shear will greatly improve the diagnosis, prevention, and treatment of foot ulcers in diabetic patients.